Built on top of Gosu, an engine for making 2-D games. Gosu provides the means to handle the graphics, sound, and keyboard/mouse events. It doesn't provide any sort of client/server network architecture for multiplayer games, nor a system for tracking objects in game-space. This gem aims to fill that gap. Originally I tried using Chipmunk as the physics engine, but its outcomes were too unpredictable for the client to anticipate the server. It was also hard to constrain in the ways I wanted. So I elected to build something integer-based. In the short term, I'm throwing anything into this gem that interests me. There are reusable elements (GameSpace, Entity, ServerPort), and game-specific elements (particular Entity subclasses with custom behaviors). Longer term, I could see splitting it into two gems. This gem, game_2d, would retain the reusable platform classes. The other classes would move into a new gem specific to the game I'm developing, as a sort of reference implementation.